I have two Swann DVR systems, one is a D1 type and the other is the 960H type. I want to add some PTZ cameras to the systems, but since I am having an extremely difficult time finding Swann PTZ cameras, I wanted to bite the bullet and try to use a different brand PTZ camera which is actually available.Has anyone done anything like this? I am thinking of getting some PTZ cameras from Lorex, Dahua, or any other brands that work with systems comparable to my Swann systems. Does anyone know if there are major compatibility problems software or hardware-wise between the different brands? Are the wire connections different between different brands? I've only used Swann, so I haven't looked into the other brands.